#include <stdio.h>
#include <unistd.h>

int global_val=100;
int main()
{
  pid_t id=fork();
  if(id<0)
  {
      printf("fork error\n");
      return 1;
  }
  else if(id==0)
  {
    int cnt=0;
    while(1)
    {printf("我是child，pid: %d,ppid: %d,global_val:%d &global_val:%p\n",getpid(),getppid(),global_val,&global_val);
    sleep(1);
    cnt++;
    if(cnt==10)
    {
      global_val=300;
      printf("子进程已经跟改了全局的变量了\n");
    }
    }
  }
  else 
  {
    while(1)
    {printf("我是parent，pid: %d,ppid: %d,global_val:%d &global_val:%p\n",getpid(),getppid(),global_val,&global_val);
    sleep(2);
    }
  }
  return 0;
}
